Rheostat with auxiliary contact system



July 10, 1923. l,46l 0?2 D. H gHEFHFF, JR

RHEOSTAT WITH AUXILIARY CONTACT SYSTEM Filed Dec. 4, 1922 3 Sheets-Sheet1 High.

INVENTOR if. 5/26/7711 J:

BY 7/; fim4W ATTORNEYS July 10, 1923 D. H. SHERIFF, JR

RHEOSTAT WITH AUXILIARY CONTACT SYSTEM 1922 3 Sheets-Sheet 2 Filed Dec.

Lame

INVENTOR I Sizen'ffi Jr:

ATTORNEYS July 10, 1923. 1,461,072

D. H. SHERHFF, JR

RHEOSTAT WITH AUXILIARY CONTACT SYSTEM Filed Dec. 4, 1922 3 Sheets-Sheet5 f9 69 2/9 E 25 26 H E 9y mm l I E 27 E 24 2 g Patented duly 1d, 1923?.

unit

DAVID HARRISON SHERIFF RHEOSTAT V7 Application filed December 4, 1

To aZZ whom it may concern:

B it known that 1, DAVID SHERIFF, a citizen or the United States,residing at Kansas City, in the county of Jackson and State of Missouri,have invented new and lmproved Rheostat with Auxiliary Contact Systems,of which the following is a specification.

My invention relates to certain new and useful improvements in,rheostats of the kind especially designed for use in radio sets and theinvention particularly has for its object to provide means in connectionwith the rheostat for connecting one or more meters in the circuit whilemanipulating the rheostat in adjusting the resistance in the circuit; toprovide a means whereby one set of meters may serve any number ctrheostat sets that may be used, without interference between the severalrheostat sets the bulbs controlled thereby.

in its general nature, the invention resides in providing a rheostat ofthe rotary spindle type with a set of auxiliary contacts de-.

signed to be controlled by the movement of the rheostat spindle,particularly while adjusting the resistance.

In its more detail nature, the invention includes a rheostat having aspindle and knob adapted to be turned to cut in or out an amount ofresistance connected in the circuit and provided with a set of auxiliarycontacts whereby while the rheostat spindle may be turned for varyingthe resistance, the auxiliary contacts may be simultaneously controlled,substantially automatically, by the operator to cut in either a voltmeter or ammeter, or both, so that the current flowing through the bulband the voltage at the bulb terminals may be indicated to the operator,the arrangement of auxiliary contacts being such, and they being socombined with the-rheostat, that one set of meters can be used with anynumber of sets of rheostats so that if there are a plurality of bulbs incircuit each with their separate rheostat controls, the operator needonly provide a single set of meters in order to cooperate with all ofthe rheostats and without the necessity of changing any wire terminalconnections be tween the meters and the line circuits, or, in otherwords, one set of meters is permanently wired up with all of therheostats but separately responsive to each rheostat manipulation.

In its'more specific nature, the invention OF KANSAS CITY, lEISEaOURE.

' CONTACT SYSTEI'JI.

Serial lilo. 604,820.

resides in thos novel details of construction, combination andarrangement or parts, all of which will be first fully explained, thenbe specifically pointed out in the appended claims and illustrated inthe accompanying drawings, in which:

Figure l is a rear view of a rheostat of the rotary type embodying myinvention.

Figure 2 is a vertical entral longitudinal section of the same, partsbeing shown in elevation.

Figure is a modification of the rheostat shown in Figures 1 and 2.

Figures 4, 5 and 6 are circuit diagrams showing how a plurality ofrheostats are connected up with one set of meters and indicating thepaths of current with different adjustments of the rheostat.

rigure 7 is a vertical section, somewhat diagrammatic, showing how theinvention may be applied to rheostats of that type wherein theresistance coil is mounted on the dial and turns with the same.

Figure 8 is a vertical section showing how the invention may be appliedto rheostats of the compression t pe.

In the drawings, in which like numerals and letters of referencedesignate like parts in all of the figures, 1 is the panel to which theinsulated block or bas 2 of the rheostat and the dial 11 thereof aresecured in any usual way. 3 is the resistance block which is mounted onthe insulating base 2 and on which is wound the resistance wire a, oneend of which is connected to the terminal post 5, as shown. 6 is thecontact spring finger whose hub 7 is secured in any suitable way to therotatable spindle 8, which is adapted to be turned on its axis by theknob 9. The latter may carry a point-er 10 to cooperate with the dial11. All of the foregoing parts are of the ordinary construction exceptthat with my arrangement the spindle 8 has aXial or longitudinalmovement as well as rotary movement, the longitudinal movement beinglimited by a suitable stop 21 in one direction and by the knob 9 in theother direction.

In carrying out my invention, I provide one or more auxiliary contactfingers mount ed on the insulating base 2 and having their contact endsprojected to cooperate with a disk 12 on the spindle 8, the disk 12 inthe preferred embodiment of the invention being rigidly mounted on thespindle and in electrical contact therewith.

In the preferred embodiment of the invention, I provide four auxiliarycontact fingers, numbered 13, 14, 15, 16, respectively, in the drawings,and secured to contact posts 17, 18, 19, 20, respectively, as shown inFigures 1 and 2 of the drawings. These auxiliary contact fingers havetheir contacting ends projected over one another as shown in Figure 1,but not in electrical connection with one another, and contact fingers14, 15 are united at the projecting ends by an insulating block 28 whichcauses the fingers 14, 15 to move in unison in a manner presentlyexplained.

In the practical arrangement of this embodiment of the invention, thedisk 12 and contact finger 13 are normally in electrical engagement (seeFigure 2) and are held normally in such engagement by the resiliency ofthe finger 6, which tends to pull the spindle 8 from right to left inFigure 2. When, however, the spindle 8 is pulled outwardly from left toright in Figure 2, the disk 12 will disengage the contact point of thefinger 13 and engage the contact point of the finger 14, thus shiftingthe circuit at the disk 12 from the contact 13 to the contact 14.Further movement from left to right in Figure 2 causes contacts 14, 15to be pushed over from left to right in Figure 2 until the contactpoints of fingers 15, 16 are in engagement.

In my embodiment of the invention illustrated in Figure 3, the contactfingers 13 to 16, inclusive, are reversed and normally the spindle 8 isheld in its right hand extremity of movement by a spring 22 whichovercomes the tension of the spring 6 but when the knob is pushedinwardly, the disk 12 will disengage the contact point 13 and engagethat of the finger 14 and on further movement cause the contact pointsof fingers 15 16 to be brought together. As best shown in Figure 3, theparts 19, 20 correspond to the parts 19 and 20 in Figure 1.

In using my invention, all of the contact points 13, 14, 15, 16 may beused or only one or more, as desired \Vhen the system on which therheostat is to be used includes a bulb 23 and a volt meter V and anammeter A, all of the auxiliary contacts are used, as shown, for examplein Figures 4, 5 and 6, by reference to which it will be seen that one ofthe line wires connects directly to the bulb 23 and to the volt meter,the other line wire connecting to the terminal 17 While the otherterminal of the bulb 23 connects to the terminals 5 and 20. The otherterminal of the volt ammeter connects to terminal 19 and the otherterminal of the ammeter connects to terminal 18. When two or more bulbsand rheostats are employed in the circuit, terminals 17 of each rheostatare connected together, terminals 18 are connected together, terminals19 are connected together but terminals 20 and 5 are individuallyconnected with their respective bulbs.

Assume the diagram shown in Figure 4 having been adjusted as indicated,the normal circuit connection from the resistance is made through thefinger 6 and disk 12 to the contact finger which is carried by theterminal 17, with the result that the current flows through the bulb,through the resistance cut in, through the contact finger 6, disk 12,finger 13 and terminal 17. Should the operator desire to adjust theresistance and at the same time get an ammeter reading, he merely pullsout on the knob (if the embodiment shown in Figures 1 and 2 is used) orpushes in on the knob 9 (if the embodiment shown in Figure 3 is used) tomove the disk 12 out of contact with the finger 13 which thereby opensthe circuit at terminal 17, (see right hand rheostat, Figure 5) andcloses the circuit with contact 14, thus causing the current to flow tocontact 18 and through the ammeter, as indicated in Figure 5, the righthand rheostat being the one under adjustment in the presentconsideration.

Now, assume the operator wishes to get a volt reading and an ammeterreading both, he moves the spindle 8 to the complete limit of itsmovement against the tension of the spring to open the circuit betweenthe spindle disk 12 and the contact finger 13 and its terminal 17 andcloses the circuit with the contact finger 14 and its terminal 18 and atthe same time closes the circuit between the fingers 15 and 16, whichproduces a current over terminals 19 and 20, thereby cutting in the voltmeter, as well as the ammeter, as shown in the left hand unit in Figure6. In this way, he can obtain the reading of both the voltage andcurrent passing through the bulb 23 of the particular unit underadjustment. Of course, if only an ammeter is used, the contacts whichcontrol the volt meter may be omitted, and vice versa.

In Figure 7 I have illustrated the manner in which my invention may beapplied to those rheostats in which the resistance coil is rotatable andthe contact finger stationary. In this figure those parts correspondingto similar parts in the preceding figures bear the same referencecharacters plus the index letter K, as 1", 4", etc. In this embodimentof the invention the dial 11 turns with the spindle 8 to vary theresistance. The spindle 8 is pushed in or pulled out to change therelation of the disk 12 with the auxiliary contacts 13, 14", 15 and 16as in the preceding embodiment illustrated and described herein;

Figure 8 shows the embodiment of my invention, adapting it to rheostatsof the compression type. In this figure those parts which functionallycorrespond with similar parts in the preceding figures bear the samememes numbers asin the preceding figures lus the indexletter y,. as,l,43,57, etc. The resistance element 44' is compressible betweenastationary plate 5 and flmovable platefi on a-screw 25 threaded intotherboxing 24 and having a uared end-26 sli'dably socketed at,27 into te endof zthe spindleS so that by turnin the s indie-the resistance maybe varied. y pus ing; in or] ulling out the spindle the relation. of.the. isks 12 to the auxiliary contacts 13, 14315- andlG may be varied asdesired, in the same way as in the preceding embodiments.

The essential feature of my invention resides in combining with arheostat an auxiliary contact system useful for cutting in circuits'orcircuit branches while manipulating the resistance adjustment of acircuit;

While I-have shown but two embodiments of the invention I desire itunderstood that modifications in the details of construction,combination and arrangement of parts may be readily made withoutdeparting from the spirit of the invention or the scope of the appendedclaims.

What I claim is:

1. In a .rheostat wherein is provided a rotary spindle and meanscooperating therewith for var ing the resistance in circuit;

a set of auxiliary contacts, and means bringing the same into action.

.2. In a rheostat wherein is provided a rotary spindle and meanscooperating'therewith for varying the resistance in circuit; a set ofauxiliary contacts, and an element on said spindle cooperating with saidauxiliary contacts 'for the purposes described.

3. In a rheostat wherein is provided a resistance element and a rotaryspindle with contact finger riding over said resistance element; a setof auxiliary contacts, and means on said spindle adapted on axialmovement of said spindle to cooperate with said auxiliary contacts.-

4. In a rheostat wherein is provided a rotary spindle, a stationaryresistance element, and a spring contact finger carried by said spindlefor engaging said resistance element to vary the resistance in circuit;of

an auxiliary contact finger, a disk on said spindle normally engagingsaid auxiliary contact finger, a second auxiliary contact. finger spacedfrom said disk, said spindle being longitudinally movable whereby saiddisk may be disengaged from the first auxiliary contact finger andengaged with the said second auxiliary contact finger, substantially asshown and described.-

5. In a rheostat wherein is rovided a rotary spindle, a stationaryresistance element, and aspiring: contact finger. fia lled by saidspindle-- for engaging saidresistance element to vary the resistance incireu-it;.o fan auxiliary contact-finger, a disk on said spin dlenormally engaging said auxiliary contact finger, a secondauxiliarycontact finger spaced from-said disk, said spindle beinglongitudinally. movable whereby said further movement of said spindle to,push' said second and third contact fingers over 6. In an apparatus ofthe character stated, a line circuit, a plurality of rheostats and bulbscontrolled thereby connected with said line circuit, a single set ofmeters, and

means on each of said rheostats and electrically connected with saidmeters whereby the manipulations of the movable element of the rheostatmay be caused to connect that particular rheostat and the bulbcontrolled thereby in circuit with said meters.

7. In an apparatus of the, character stated, a line circuit, a luralityof rheostats and bulbs controlled t ereby connected to said linecircuit, a single set of meters and cooperative connections andmechanisms between said meters and the several rheostats whereby atleast one of said meters may be electrically connected to the bulbcircuit of any rheostat by manipulation of the rheostat. adjustmentelement.

8. In a rheostat wherein is provided a rotary sgindle, a resistanceelement, a spring contact nger for engaging with said resistanceelementto vary the resistance in air cuit; of an auxiliary contactfinger, a disk on said spindle movably engaging said auxiliary contactfinger, said disk being axially movable to engage and disengage saidauxiliary contact finger.

9. In a rheostat wherein is provided a rotary spindle, a. resistanceelement, a, spring contact finger for engaging with said resistanceelement to vary the resistance-in circuit; of an auxiliary contactfinger, a

. disk onsaid spindle movably engaging said auxiliary contact finger,said disk being axially movable to engage and disengagesaid auxiliarycontact nger, and other auxiliary contact fingers adapted to becontrolled by the movements of said disk.

Dim HARRISON si IEnrFF. JR.

